Ready to do your banking at home a via TV?

Banking from home over your television screen may be coming sooner than you think: * Some 200 families in Columbus, Ohio, have been playing their bills and checking their account balances from home for the last three months under an experiment known as Bankone, which ties a home computer to their telephone lines.

* Security Pacific National Bank in San Diego is about to launch a similar experiment tied to cable TV.

* And in Knoxville, Tenn., a joint venture by a bank services company and a retail electronics company expects to equip 400 homes for banking by Christmas. Business leaders insist the Tennessee offering, which is a franchise other banks may decide to adopt, is intended not as an experiment but as an ongoing service that can be expanded to as many customers as want it.

"We're using all proven technology," insists Thomas E. Sudman, president and chief executive officer of United American Services Corporation in Knoxville. "the only thing we're adding is a small keyboard which plugs into the TV set and telephone."

Some experts in the field predict that banking at home may become commonplace as soon as the mid-1980s. But whatever its spread and timing, the idea is not without a few drawbacks. It can save waiting in ling lines for many routine transactions but can never substitute for the bank itself nor for an automated teller machine in making cash deposits and withdrawals. The advantage of banking at home is mainly its potential for instructing the bank to pay your bills and getting information about your account.

"You won't write checks or lick stamps," notes John Fisher, senior vice-president of Bankone in Columbus. As a experiment participant, Mr. Fisher paid 45 bills by home computer in the last two months. "I think it will change the customer's habit of feeling he must use a checkbook and paper for every transaction."

But the real holdup, most experts agree, is that as yet it makes little economic sense to plug in a home computer just for banking. That's why the Knoxville plan, available for $25 to $30 a month, also allows customers to use the computer to play games, compute budgets and taxes, and to bring up on the screen as many as 11 newspapers and daily quotations.